Generally, an ABS (acrylonitrile-butadiene-styrene) resin has a good balance of properties such as processability, rigidity, chemical resistance, impact resistance, and the like such that it has been widely used for various products such as automobiles, electrical/electronic appliances, office automation (OA) devices, toys, stationery, and the like. Recently, demand for a thermoplastic resin with superior scratch resistance is increasing as the use of thermoplastic resin without a coating to protect the environment is becoming a widespread trend. There is also a need for a thermoplastic resin with low gloss as customers increasingly prefer products with a high quality appearance.
Generally, ABS resin includes butadiene based rubber to improve impact resistance. However, the butadiene based rubber substantially lowers scratch resistance, which increases the susceptibility of final molded articles to damage from scratching during transport. Further, a conventional ABS resin does not provide a high quality appearance since it is too glossy.
U.S. Pat. No. 6,448,342 discloses a method stated to improve transparency of a butadiene based rubber reinforced resin by grafting vinyl compound, cyanide vinyl compound, and alkyl methacrylate with a butadiene rubber having a average particle size ranging from 150 to 350 nm and a specific rubber particle size distribution.
U.S. Patent Publication No. 2007-0203293 discloses a compounding method using a block copolymer comprising an acrylate-styrene-acrylonitrile graft copolymer, an aromatic vinyl compound-cyanide vinyl compound copolymer, an aromatic vinyl compound-cyanide vinyl compound-alkyl methacrylate terpolymer, and a di-block copolymer (aromatic vinyl compound/cyanide vinyl compound-alkyl methacrylate/aromatic vinyl compound/cyanide vinyl compound). However, the resins of the foregoing patents still have disadvantages, including insufficient scratch resistance (B level or so scratch resistance measured in terms of pencil hardness) and high glossy appearance.
U.S. Pat. Nos. 5,475,053 and 4,652,614 disclose a method for lowering resin gloss by using a spherical graft copolymer as a matting agent.
Additionally, U.S. Pat. Nos. 4,668,737 and 5,237,004 disclose a method for lowering resin gloss by using a spherical rubber particle having a core/shell structure of 0.05 to 20 μm or 2 to 15 μm.
However, the use of additives can cause exfoliation, deterioration of physical properties, and partial high gloss, in addition to increasing production costs. Further, when using a rubber particle, the resins may have low gloss but also low scratch resistance.
As described above, although there has been many attempts to obtain low gloss characteristic while maintaining high scratch resistance, it has been difficult to improve both scratch resistance and low gloss characteristic at the same time since high scratch resistance is usually accompanied by high gloss, and, conversely, low scratch resistance is accompanied by low gloss.